1. Field of the Invention
The present invention relates to a stage apparatus which moves a movable stage in two orthogonal directions in a plane, and a camera shake correction apparatus using the stage apparatus.
2. Description of the Prior Art
A known stage apparatus used as a camera shake correction apparatus in which a movable stage is moved in two orthogonal directions in a plane is described in, for example, Japanese laid-open patent publications H8-304868 and H8-152659.
Such a known stage apparatus (shake correction apparatus) has a structure which will be discussed hereinafter. Namely, a Y-direction guide member which projects from one of opposite surfaces of a stationary support plate (stationary support base-plate) is provided with a Y-direction linear slot which is elongated in a specific direction (Y-direction), and one of the two rod portions of a Y-direction movable rod (Y-direction movable member), which are angled relative to each other to have the shape of a letter L, is slidably engaged in the Y-direction linear slot so that the Y-direction movable rod is linearly guided in the Y-direction. A projecting portion which projects from a movable stage (X-direction movable member) to which a correction lens is fixed is provided with an X-direction linear slot which is elongated in an X-direction orthogonal to the Y-direction, and the other of the aforementioned two rod portions of the Y-movable rod is slidably engaged in the X-direction linear slot so that the movable stage is linearly guided in the X-direction by the other rod portion of the Y-direction movable rod. In addition, front and rear surfaces of the movable stage are supported at three points thereon by positioning members so that the movable stage remains lying in a plane (X-Y imaginary plane) parallel to both the X- and Y directions.
If an actuator gives the above-described movable stage a linear moving force in the X-direction, the movable stage linearly moves in the X-direction in the X-Y imaginary plane along the aforementioned other rod portion of the Y-direction movable rod. If the actuator gives the movable stage a linear moving force in the Y-direction, the aforementioned one rod portion of the Y-direction movable rod linearly moves in the Y-direction in the X-Y imaginary plane along the Y-direction linear slot, which causes the movable stage to move together linearly in the Y-direction.
Accordingly, the correction lens is moved in the X and Y directions to correct camera shake (i.e., to stabilize an object image which is to be photographed) by driving the actuator in accordance with shake information detected by a shake detection sensor provided in a camera.
However, the structure of the stage apparatus disclosed in Japanese laid-open patent publications H8-304868 is complicated because the stage apparatus needs to be provided with positioning members which support front and rear surfaces of the movable stage at three points in addition to the stationary support plate, the Y-direction movable member and the movable stage (X-direction movable member).
To overcome such a problem, the assignee of the present invention has proposed a stage apparatus which includes: a stationary support plate; a Y-direction movable member which is supported on the stationary support plate to be movable in a specific Y-direction; and an X-direction movable member (movable stage) which is supported on the Y-direction movable member to be movable in an X-direction orthogonal to the Y-direction, wherein the Y-direction movable member includes a Y-direction rod portion which extends in the Y-direction and a pair of X-direction rod portions which are connected to the Y-direction rod portion and extend in the X-direction, the stationary support plate includes a Y-direction guide device for guiding the Y-direction rod portion of the Y-direction movable member so as to slide in the Y-direction, and a Y-direction support device for supporting free ends of the pair of X-direction rod portions so as to allow movement of each X-direction rod portion in the Y-direction, and the X-direction movable member is supported by the Y-direction movable member so as to slide in the X-direction. This stage apparatus is disclosed in Japanese Patent Application 2004-13563.
In this stage apparatus, if all the Y-direction rod portion and the pair of X-direction rod portions of the Y-direction movable member do not lie in one plane, the Y-direction movable member cannot move smoothly relative to the stationary support plate while the movable stage (X-direction movable member) cannot move in the X-direction smoothly relative to the Y-direction movable member either, which deteriorates the operating characteristics of the stage apparatus.
Nevertheless, it is generally the case that the Y-direction movable member is molded as a single member, and it is not easy for the Y-direction movable member to be molded so that all of the Y-direction rod portion and the pair of X-direction rod portions of the Y-direction movable member lie in one plane with a high degree of precision. Moreover, it is difficult to make all of the Y-direction rod portion and the pair of X-direction rod portions of the Y-direction movable member lie in one plane after the completion of molding of the Y-direction movable member by adjusting the angle between the axis of the Y-direction rod portion and the axis of each X-direction rod portion.